1. Field of the Invention
The present invention relates to an image display apparatus, and more particularly to a projection image display apparatus that displays a three-dimensional image.
2. Description of the Related Art
Recently, a liquid crystal projector (a projection image display apparatus) that displays a three-dimensional image using polarized lights orthogonal to each other is proposed. This liquid crystal projector simultaneously projects images for the right and left eyes on the same screen in polarization states different from each other. A user observes the images so as to enter the respective eyes using an analyzer such as a polarization plate or a circular polarization plate to be able to observe the three-dimensional image.
Japanese Patent Laid-Open No. 2009-122430 discloses a liquid crystal projector that displays a three-dimensional image by disposing image display elements for the right and left eyes in one liquid crystal projector to illuminate these image display elements using polarized lights different from each other to synthesize and projects each image light by a polarization splitting element.
However, in the liquid crystal projector disclosed in Japanese Patent Laid-Open No. 2009-122430, an analyzing axis of a polarization plate and a polarizing axis of the image may be shifted from each other. The polarizing axis means a direction of vibration of linear polarized light or a direction of an elliptical long axis of elliptical polarized light. When the analyzing axis of the polarization plate and the polarizing axis of the image are shifted from each other, a phenomenon in which a certain image for the right eye enters the left eye and a certain image for the left eye enters the right eye, which is called crosstalk, is generated. As a result, the quality of the three-dimensional image is deteriorated and therefore it is difficult for the user to obtain a three-dimensional appearance. Particularly in a liquid crystal projector using a prism-type polarization splitting element, the crosstalk is generated depending on intensity or an incidence azimuth of a light beam that enters the polarization splitting element and therefore the quality of a display image may be significantly deteriorated.